Lawn-Boy GoldPro Series User manual

Operator’s Manual
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Lawn-Boy Inc., Attn: Parts Dept., 8111 Lyndale Ave S, Bloomington, MN 55420-1196.
Domestic English (EN)
Form No. 3325-494 Rev A
GoldPro Series
Walk Power Lawn Mower
10424—210000001 and Up
10550—210000001 and Up
10552—210000001 and Up

2
All Rights Reserved
Printed in the USA
2001 by Lawn-Boy, Inc.
8111 Lyndale Avenue South
Bloomington, MN 55420-1196
The engine exhaust from this product contains
chemicals known to the State of California to
cause cancer, birth defects, or other reproductive
harm.
Warning
Important This engine is not equipped with a spark
arrester muffler. It is a violation of California Public
Resource Code Section 4442 to use or operate this engine
on any forest–covered, brush–covered or grass–covered
land. Other states or federal areas may have similar laws.
This spark ignition system complies with Canadian
ICES-002.
Ce système d’allumage par étincelle de véhicule est
conforme à la norme NMB-002 du Canada.
The enclosed Engine Owner’s Manual is supplied for
information regarding The U.S. Environmental
Protection Agency (EPA) and the California Emission
Control Regulation of emission systems, maintenance
and warranty.
Keep this engine Owner’s Manual with your unit.
Should this engine Owner’s Manual become damaged
or illegible, replace immediately. Replacements may be
ordered through the engine manufacturer.
Contents
Page
Introduction 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Lawn Mower Safety 3. . . . . . . . . . . . . . . .
Safety and Instruction Decals 5. . . . . . . . . . . . . . .
Assembly 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing the Handle 6. . . . . . . . . . . . . . . . . . . . . .
Installing the Starter Rope 6. . . . . . . . . . . . . . . . . .
Adjusting the Handle Height 6. . . . . . . . . . . . . . . .
Installing the Cover Plate 7. . . . . . . . . . . . . . . . . . .
Installing the Fuse 7. . . . . . . . . . . . . . . . . . . . . . . .
Before Starting 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mixing Gasoline and Oil 8. . . . . . . . . . . . . . . . . . .
Operation 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controls 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting the Engine 10. . . . . . . . . . . . . . . . . . . . . . . .
Stopping the Engine 10. . . . . . . . . . . . . . . . . . . . . . .
Using the Self-propel Drive 11. . . . . . . . . . . . . . . . .
Pulling the Lawn Mower Rearward 11. . . . . . . . . . .
Adjusting the Cutting Height 11. . . . . . . . . . . . . . . .
Operating Tips 11. . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended Maintenance Schedule 13. . . . . . . .
Cleaning the Lawn Mower Housing 14. . . . . . . . . .
Cleaning under the Belt Cover 15. . . . . . . . . . . . . .
Lubricating the Self-propel Drive 15. . . . . . . . . . . .
Adjusting the Self-propel Drive Cable 16. . . . . . . .
Servicing the Air Filter 16. . . . . . . . . . . . . . . . . . . .
Maintaining the Spark Plug 17. . . . . . . . . . . . . . . . .
Maintaining the Cutting Blade 17. . . . . . . . . . . . . .
Cleaning the Exhaust Port 18. . . . . . . . . . . . . . . . . .
Changing the Fuse 19. . . . . . . . . . . . . . . . . . . . . . . .
Charging the Battery 19. . . . . . . . . . . . . . . . . . . . . .
Disposing of the Battery 20. . . . . . . . . . . . . . . . . . .
Emptying the Fuel Tank 20. . . . . . . . . . . . . . . . . . . .
Storage 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preparing the Fuel System 20. . . . . . . . . . . . . . . . . .
Preparing the Engine 20. . . . . . . . . . . . . . . . . . . . . .
Folding the Handle 21. . . . . . . . . . . . . . . . . . . . . . . .
Removing from Storage 21. . . . . . . . . . . . . . . . . . . .
Accessories 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing a Rear Grass Catcher 21. . . . . . . . . . . . . .
Installing the Mulch Plate 23. . . . . . . . . . . . . . . . . .
Troubleshooting 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Federal Emission Control Warranty Statement 26. . . . .
The Lawn-Boy No-Worry Warranty 28. . . . . . . . . . . . .
Important The two-stroke engine provided on this
product meets the EPA Phase I Non-Road Emissions
regulations for engines under 19 kW. This product does
not meet CARB TIER 1 regulations and cannot be sold in
California.
Introduction
Read this manual carefully to learn how to operate and
maintain your product properly. The information in this
manual can help you and others avoid injury and product
damage. Although Lawn-Boy designs and produces safe
products, you are responsible for operating the product
properly and safely.
Whenever you need service, genuine Lawn-Boy parts, or
additional information, contact an Authorized Service
Dealer or Lawn-Boy Customer Service and have the
model and serial numbers of your product ready. Figure 1
illustrates the location of the model and serial numbers on
the product.

3
m-5307
1
Figure 1
1. Locationof the model and serial numbers
Write the product model and serial numbers in the space
below:
Model No.
Serial No.
This manual identifies potential hazards and has special
safety messages that help you and others avoid personal
injury and even death. Danger, Warning, and Caution are
signal words used to identify the level of hazard.
However, regardless of the hazard, be extremely careful.
Danger signals an extreme hazard that will cause serious
injury or death if you do not follow the recommended
precautions.
Warning signals a hazard that may cause serious injury or
death if you do not follow the recommended precautions.
Caution signals a hazard that may cause minor or
moderate injury if you do not follow the recommended
precautions.
This manual uses two other words to highlight
information. Important calls attention to special
mechanical information and Note: emphasizes general
information worthy of special attention.
Safety
This lawn mower meets or exceeds the CPSC blade
safety requirements for walk-behind rotary lawn
mowers and the B71.1 specifications of the American
National Standards Institute in effect at the time of
production.
Improperly using or maintaining this lawn mower can
result in injury. To reduce the potential for injury,
comply with these safety instructions.
Lawn-Boy designed and tested this lawn mower for to
offer reasonably safe service; however, failure to comply
with the following instructions may result in personal
injury.
Engine exhaust contains carbon monoxide, an
odorless, deadly poison that can kill you.
Do not run the engine indoors or in an enclosed
area.
Warning
To ensure maximum safety, best performance, and to
gain knowledge of the product, it is essential that you
and any other operator of the lawn mower read and
understand the contents of this manual before the
engine is ever started. Pay particular attention to the
safety alert symbol which means caution, warning,
or danger — “personal safety instruction.” Read and
understand the instruction because it has to do with
safety. Failure to comply with the instruction may
result in personal injury.
General Lawn Mower Safety
The following instructions have been adapted from the
ANSI/OPEI standard B71.1—1998 and ISO standard
5395:1990(E). Information or terminology specific to
Lawn-Boy lawn mowers is enclosed in parenthesis.
This lawn mower is capable of amputating hands and feet
and of throwing objects. Failure to observe the following
safety instructions could result in serious injury or death.
Training
•Read this operator’s manual carefully. Be thoroughly
familiar with the controls and the proper use of the
lawn mower before starting it.
•Never allow children to operate the lawn mower.
Local regulations may restrict the age of the operator.
•Never allow adults unfamiliar with these instructions
to operate the lawn mower.
•Never mow while people (especially children) or pets
are nearby. Stop the lawn mower if anyone enters the
area.
•Tragic accidents can occur if the operator is not alert
to the presence of children. Children are often
attracted to the lawn mower and the mowing activity.
Never assume that children will remain where you last
saw them.
•Keep children out of the mowing area and under the
watchful care of a responsible adult.
•Be alert and turn the lawn mower off if children enter
the area.
•Use extra care when approaching blind corners,
shrubs, trees, or other objects that may obscure vision.

4
•Keep in mind that the operator or user is responsible
for accidents or hazards occurring to other people or
their property.
•See the manufacturer’s instructions for proper
operation and installation of accessories. Use only the
accessories that are approved by the manufacturer.
Preparation
•Thoroughly inspect the area where you will use the
lawn mower, and remove all stones, sticks, wires,
bones, and other foreign objects.
•While mowing, always wear substantial footwear and
long trousers.
•Do not operate the lawn mower when barefoot or
wearing open sandals.
•Always wear safety goggles or safety glasses with side
shields when operating the lawn mower.
•Warning: Gasoline is highly flammable. Take the
following precautions:
– Store fuel in containers specifically designed for
this purpose.
– Refuel outdoors only and do not smoke while
refuelling.
– Add fuel before starting the engine. Never remove
the cap of the fuel tank or add gasoline while the
engine is running or when the engine is hot.
– If gasoline is spilled, do not attempt to start the
engine. Move the lawn mower away from the area
of spillage to avoid creating any source of ignition
until the gasoline vapors have dissipated.
– Replace all fuel tank and container caps securely.
– If you must drain the fuel from the fuel tank, do it
outdoors.
•Replace faulty mufflers.
•Before using, always visually inspect the blades, blade
bolts, and cutter assembly for wear or damage.
Replace worn or damaged blades and bolts in sets to
preserve balance.
•On multibladed lawn mowers, use care as rotating one
blade can cause the other blades to rotate.
Operation
•Do not operate the engine in a confined space where
dangerous carbon monoxide fumes can collect.
•Mow only in daylight or in good artificial light.
•Always be sure of your footing on slopes.
•Walk; never run.
•Keep a firm hold on the handle.
•For wheeled rotary lawn mowers, mow across the face
of slopes, never up and down.
•Exercise extreme caution when changing the direction
on slopes.
•Do not mow excessively steep slopes.
•Use extreme caution when reversing or pulling the
lawn mower toward you.
•Before and while moving backward, look behind and
down for small children.
•Stop the blade(s) if you must tilt the lawn mower for
transportation when crossing surfaces other than grass
and when transporting the lawn mower to and from the
area to be mowed.
•Never operate the lawn mower with damaged or
missing guards or shields, or without safety devices
(such as deflectors and grass catchers) in place.
•Do not change the speed settings on the engine.
•Disengage all blade and drive clutches before starting
the engine.
•Start the engine carefully according to instructions and
with feet well away from the blade(s).
•Do not tilt the lawn mower when starting the engine,
unless you must tilt the lawn mower to start it. In this
case, do not tilt it more than absolutely necessary and
lift only the part which is away from the operator.
•Do not start the engine when standing in front of the
discharge chute.
•Do not put your hands or feet near or under rotating
parts. Keep clear of the discharge opening at all times.
•Never pick up or carry a lawn mower while the engine
is running.
•Stop the engine and disconnect the spark-plug wire:
– before clearing blockages or unclogging the chute;
– before checking, cleaning, or working on the lawn
mower;
– after striking a foreign object. Inspect the lawn
mower for damage and make repairs before starting
and operating the lawn mower; and
– if the lawn mower starts to vibrate abnormally
(check it immediately).
•Stop the engine:
– whenever you leave the lawn mower; and
– before refuelling.

5
•Reduce the throttle setting during engine run-out and,
if the engine has a shutoff valve, turn the fuel off after
mowing.
•Stop the blade(s) when crossing gravel drives, walks,
or roads.
•Shut the engine off and wait until the blade comes to a
complete stop before removing the grass catcher.
•Do not operate the lawn mower while under the
influence of alcohol or drugs.
•If the lawn mower should start to vibrate abnormally,
stop the engine and check immediately for the cause.
Vibration is generally a warning of trouble.
Slopes are a major factor related to slip and fall accidents
which can result in a severe injury. If you feel uneasy on a
slope, do not mow it.
•Watch for holes, ruts, or bumps. Tall grass can hide
obstacles.
•Do not mow near drop-offs, ditches, or embankments.
You could lose your footing or balance.
•Do not mow on wet grass. Reduced footing could
cause slipping.
Maintenance and Storage
•Keep all nuts, bolts (especially blade attachment
bolts), and screws tight to ensure that the lawn mower
is in safe working condition.
•Never store the lawn mower with gasoline in the tank
inside a building where fumes may reach an open
flame or spark.
•Allow the engine to cool before storing the lawn
mower in any enclosure.
•To reduce the fire hazard, keep the engine, muffler,
battery compartment, and gasoline storage area free of
grass, leaves, or excessive grease.
•Check the grass catcher frequently for wear or
deterioration.
•Replace worn or damaged parts.
•Use extra care when handling gasoline; gasoline
vapors are explosive.
•Never tamper with safety devices. Check their proper
operation regularly.
•Keep the lawn mower free of grass, leaves, or other
debris buildup. Clean up any oil or fuel that spills.
•Stop and inspect the lawn mower if you strike an
object. Repair the lawn mower, if necessary, before
starting the engine.
•Never attempt to make wheel height adjustments while
the engine is running.
•Grass catcher components are subject to wear, damage,
and deterioration, which could expose moving parts or
allow objects to be thrown. Frequently check the
components and replace them with the manufacturer’s
recommended parts when necessary.
•Lawn mower blades are sharp and can cut. Wrap the
blade(s) or wear gloves, and use extra caution when
servicing them.
•Do not change the speed settings on the engine.
•If you must drain the fuel from the fuel tank, do it
outdoors.
•To ensure the best performance and safety, purchase
only genuine Lawn-Boy replacement parts and
accessories.
•Maintain or replace safety and instruction decals when
necessary.
Safety and Instruction Decals
Safety decals and instructions are easily visible to the operator and are located near any
area of potential danger. Replace any decal that is damaged or lost.
On Mower Housing
(Part No. 43-8480) On Mower Housing
(Part No. 93-7250)

6
Assembly
Note: Determine the left and right sides of the machine
from the normal operating position.
Installing the Handle
Folding or unfolding the handle improperly can
pinch, stretch, or damage one or more of the
cables. Any pinched, stretched, or damaged cable
may cause an operational failure that results in an
unsafe operating condition.
•Do not pinch, stretch, or damage the cables.
•Handle the cables with care when folding or
unfolding the handle.
•Do not use the lawn mower if one or more of
the cables are pinched, stretched, or damaged.
Contact your Authorized Service Dealer.
Warning
1. Lay the upper handle on the ground behind the lawn
mower with the handle label facing up.
2. Rotate the lower handle toward the rear of the lawn
mower and insert the bottom of the lower handle ends
into the pins as shown in Figure 2.
2
13
4
5
6
m-5309
Figure 2
1. High setting hole (2)
2. Low setting hole (2)
3. Lawn mower housing
4. Traction cable bracket
5. Pin (2)
6. Bottom of lower handle
end (2)
Note: Figure 2 shows the handle for models 10550 and
10552 only.
3. Insert the traction cable bracket in place as shown in
Figure 2 (models 10550 and 10552 only).
4. Insert a lock washer and wing nut in either the high
setting hole or low setting hole as shown in Figure 2.
To set the handle height, see Adjusting the Handle
Height on page 6.
5. Install the upper handle section onto the lower handle
section until the lower handle section nests inside the
upper handle section.
6. Install two bolts and knobs (from the loose parts bag)
to fasten the bottom of the upper handle section to the
lower handle section.
7. Tighten the upper knobs on the upper handle section.
8. Assemble the handle knobs and handle screws and
tighten them securely.
Installing the Starter Rope
Pull the starter rope through the rope guide on the handle
(Fig. 3).
Figure 3
1. Rope guide 2. Starter rope
Note: To install the starter rope more easily, squeeze the
blade control bail (Fig. 13).
Adjusting the Handle Height
You can set the handle to the high or low settings (Fig. 2).
Select the handle height setting most comfortable for you.
Align the holes in the lower handle section with the holes
in the lawn mower housing. Use the hardware shown in
Figure 2 to secure the handle to the lawn mower housing.
Note: For self-propel models, match the holes in the
traction cable bracket to the holes in the left side of the
lawn mower housing. Secure the bracket with the handle
hardware (Fig. 2).

7
Installing the Cover Plate
Your lawn mower comes with a cover plate. For side
discharge operation, install the cover plate into the deck
opening.
An uncovered discharge opening could allow the
lawn mower to throw objects in the operator’s or
bystander’s direction and result in serious injury.
Also, contact with the blade could occur.
Never operate the lawn mower unless you install a
cover plate, a mulch plate, or a grass chute and
catcher.
Warning
1. Stop the engine and wait for all moving parts to stop.
2. Disconnect the wire from the spark plug (Fig. 4)
before installing or removing the cover plate.
m–3833
1
Figure 4
1. Spark plug wire
3. Remove the knob that fastens the cover plate to the
housing (Fig. 5).
m-1726
1
2
Figure 5
1. Cover plate 2. Knob
Note: You do not need to remove or loosen the two
shoulder bolts on the housing that protrude through the
slotted holes in the cover plate. The cover plate moves
over the shoulder bolt heads (Fig. 6).
995
1
Figure 6
1. Shoulderbolt
4. Slide the cover plate clockwise to install it or slide
counterclockwise to remove it.
5. Secure the cover plate with the knob.
6. Connect the wire to the spark plug (Fig. 4).
Installing the Fuse
Electric Start Model only
The fuse protects the electric starter. If the battery does
not charge or the engine does not turn with the electric
starter, the fuse may be blown. Use a 40-amp plug-in type
fuse.
1. Remove the battery box cover (Fig. 7).
m-5146
1
2
Figure 7
1. Battery box 2. Battery box cover
Note: Use a flat-head screw driver to unclip the
battery cover (Fig. 8). Unclip both ends of the battery
cover before removing it to prevent damaging it.
m–5147
Figure 8

8
2. Install the fuse in the fuse holder as shown in Figure 9.
m-4796
1
2
Figure 9
1. Fuse Holder 2. Fuse
3. Install the battery box cover.
Before Starting
Mixing Gasoline and Oil
Your Lawn-Boy lawn mower is powered by a two-cycle
engine which requires a 32:1 mixture of gasoline and oil.
Use only clean, fresh, lead-free gasoline (including
oxygenated or reformulated gasoline) with an octane
rating of 87 or higher. To ensure freshness, purchase only
the amount of gasoline you expect to use in 30 days.
Using unleaded gasoline results in fewer combustion
chamber deposits and longer spark plug life.
Important Do not use methanol, gasoline containing
methanol, gasohol containing more than 10% ethanol,
premium gasoline, or white gas. Using these fuels can
damage the engine’s fuel system.
Important Do not use automotive oil (i.e., SAE 30 or
10W30), a two-cycle oil that is not NMMA
TCW III-certified, or a fuel mixed at the wrong
gasoline/oil ratio. This can cause engine damage not
covered under the Lawn-Boy warranty.
Danger
In certain conditions, gasoline is extremely
flammable and highly explosive. A fire or
explosion from gasoline can burn you and others
and can damage property.
•Fill the fuel tank outdoors, in an open area, and
when the engine is cold. Wipe up any gasoline
that spills.
•Do not fill the fuel tank completely full. Add
gasoline to the fuel tank until the level is 1/4 to
1/2 in. (6 to 13 mm) below the bottom of the
filler neck. This empty space in the tank allows
the gasoline to expand.
•Never smoke when handling gasoline, and stay
away from an open flame or where a spark may
ignite the gasoline fumes.
•Store gasoline in an approved fuel container
and keep it out of the reach of children.
•Never buy more than a 30-day supply of
gasoline.
Danger
When fueling, under certain circumstances, a
static charge can develop, igniting the gasoline. A
fire or explosion from gasoline can burn you and
others and damage property.
•Always place gasoline containers on the ground
and away from your vehicle before filling.
•Do not fill gasoline containers inside a vehicle
or on a truck or trailer bed because interior
carpets or plastic truck bed liners may insulate
the container and slow the loss of any static
charge.
•When practical, remove gasoline-powered
equipment from the truck or trailer and refuel
the equipment with its wheels on the round.
•If this is not possible, then refuel such
equipment on a truck or trailer from a portable
container, not from a gasoline dispenser nozzle.
•If you must use a gasoline dispenser nozzle,
keep the nozzle in contact with the rim of the
fuel tank or container opening at all times until
fueling is complete.
Use only Lawn-Boy Generation II 2-Cycle Oil (Fig. 10) or
an equivalent premium grade, NMMA TCW III-certified
two-cycle ashless oil.

9
Figure 10
Lawn-Boy Generation II 2-Cycle Oil is formulated
specifically for Lawn-Boy two-cycle engines and is
available from your Lawn-Boy retailer. Using Lawn-Boy
Generation II 2-Cycle Oil regularly will help keep your
engine clean, reduce spark plug fouling, piston ring
sticking, and pre-ignition. It also minimizes varnish
buildup, combustion chamber deposits, and exhaust port
blockage.
Substitute oils may produce more exhaust smoke, require
more frequent engine service, and reduce engine life.
Note: Failing to use the proper oil or the 32:1
gasoline-to-oil mixture ratio can result in serious engine
damage.
Add Lawn-Boy Generation II 2-Cycle Oil (Fig. 10) or an
equivalent oil to fresh, unleaded gasoline according to the
chart below:
32:1 Gasoline-to-Oil Ratio Mixing Chart
Gasoline Oil
1 gallon (3.8 liters) 4 ounces (118 ml)
2 gallons (7.6 liters) 8 ounces (237 ml)
5 gallons (19 liters) 20 ounces (591 ml)
To properly mix the gasoline and oil:
1. Pour half of the desired amount of fresh, unleaded
gasoline into a clean, approved gasoline container.
2. Add the full amount of Lawn-Boy Generation II
2-Cycle Oil (Fig. 10) or an equivalent oil to the
gasoline.
3. Install the cap on the gasoline container.
4. Shake the gasoline-and-oil mixture thoroughly.
5. Slowly remove the cap and add the remaining amount
of gasoline.
Note: Do not mix gasoline and oil in the fuel tank. Oil at
room temperature mixes easier and more thoroughly than
cold oil. Oil below 32°F (0°C) requires additional mixing.
111
123
Figure 11
1. Add oil to half of the
gasoline
2. Install the cap and shake
the can to mix
3. Add the remaining amount
of gasoline
Important Do not overfill the fuel tank. The
gasoline/oil mix must have room to expand.
Important Do not use fuel additives except a fuel
stabilizer during storage. Do not use fuel stabilizers
with an alcohol base such as ethanol, methanol, or
isopropanol. You do not need a stabilizer if you use
Lawn-Boy Generation II 2-Cycle Oil (Fig. 10).
6. Clean around the fuel cap (Fig. 12).
m–3833
1
2
Figure 12
1. Fuel cap 2. Primer
7. Remove the fuel cap and fill the fuel tank with the
gasoline-and-oil mixture to within 1/4 inch (6 mm)
from the top of the tank. Do not fill into the filler
neck.
8. Install the fuel cap securely and wipe up any spilled
fuel.

10
Operation
Note: Determine the left and right sides of the machine
from the normal operating position.
Controls
The starter handle, the blade control bail, and the throttle
control are on the upper handle as shown in Figure 13.
3
21
m–5308
4
Figure 13
1. Bladecontrol bail
2. Upper handle 3. Starter handle 4. Throttle control
Note: Figure 13 shows the handle for models 10550 and
10552 only.
Starting the Engine
1. Ensure that the wire is connected to the spark plug
(Fig. 14).
m–3833
1
Figure 14
1. Spark plug wire
2. When starting a cold engine, move the throttle lever to
the Choke position (Fig. 15).
1051
1
Figure 15
1. Throttlelever
3. Push the primer three times, waiting about two
seconds between each push (Fig. 12).
Note: To start a warm engine, move the throttle to the
Fast position and press the primer no more than once.
4. Hold the blade control bail against the upper handle
(Fig. 13).
5. Start the lawn mower.
Electric Starting (Electric Start Model only):
Turn the key clockwise to the Start position and
release the key when the engine starts (Fig. 16).
1352
Figure 16
1. Key
Manual Starting:
Pull the starter handle (Fig. 13) lightly until you feel
resistance, then pull sharply. Let the rope return to the
handle slowly.
6. If the engine fails to start, repeat steps 3 through 5.
Stopping the Engine
1. Move the throttle lever to the Slow position
(Fig. 15).
2. Release the blade control bail. Both the engine and the
blade will stop. Contact your Authorized Service
Dealer immediately if they do not.
3. Remove the key from switch if you leave the lawn
mower unattended (electric start model only).

11
Using the Self-propel Drive
Self-propel Models only
To operate the self-propel drive, simply walk forward with
your hands on the upper handle. As you move forward,
the upper handle will slide toward the lawn mower,
activating the self-propel drive. The faster you walk, the
farther the handle will slide and the faster the lawn mower
will propel (Fig. 17).
m–4206
Figure 17
Note: The lawn mower propels at the maximum speed
when you push in the upper handle as far forward as
possible.
To slow down the drive, simply slow your walking speed;
to stop the drive, stop walking (Fig. 17).
Pulling the Lawn Mower
Rearward
The lawn mower comes with free-wheeling clutches that
make it easier to pull the lawn mower backward. These
clutches disengage when you roll the lawn mower forward
with the self-propel drive disengaged.
To pull the lawn mower backward with ease, do the
following:
1. Stop the lawn mower 4 to 6 inches (10 to 15
centimeters) before you reach the point where you
want to pull it backward.
2. When you stop walking, hold your elbows at your
sides and do not extend your arms forward.
Note: As the momentum of the lawn mower carries it
forward (away from you), the self-propel drive should stop
driving. From that point, the lawn mower must roll
forward another 1 to 2 inches (3 to 5 centimeters) to
disengage the clutches.
3. Pull the lawn mower backward.
4. To engage the self-propel drive again, start walking.
If these steps do not work, the lawn mower may not have
had enough momentum to roll far enough. Another way to
disengage the clutches is to reach below the upper handle
to the metal tube and push the lawn mower forward a
couple of inches (centimeters). This will not engage the
drive and should give the clutches the free wheeling they
need. If you cannot disengage the self-propel drive using
these methods, contact an Authorized Service Dealer.
Adjusting the Cutting Height
You can adjust each wheel individually with a wheel
height adjustment lever. Cutting heights are 1 inch
(25 mm); 1-1/2 inch (38 mm); 2 inch (51 mm); 2-1/2 inch
(64 mm); 3 inch (76 mm); and 3-1/2 inch (89 mm).
Danger
Adjusting the cutting height levers could bring
your hands into contact with a moving blade and
result in serious injury.
•Stop the engine and wait for all movement to
stop before adjusting the cutting height.
•Do not put fingers under the housing when
adjusting the cutting height.
1. Pull the wheel height adjustment lever toward the
wheel and move it to the desired position (Fig. 18).
1018
1
Figure 18
1. Wheelheight adjustment lever
2. Release the wheel height adjustment lever and seat it
securely in the desired notch.
Note: Set all four wheels to the same height.
Operating Tips
•Review the safety instructions and read this manual
carefully before operating the lawn mower.
•Clear the area of sticks, stones, wire, branches, and
other debris that the lawn mower could pick up or the
blade could hit and throw objects.
•Keep everyone, especially children and pets, away
from the area of operation.
•Avoid striking trees, walls, curbs, or other solid
objects. Never deliberately mow over any object.

12
•If the lawn mower strikes an object or starts to vibrate,
immediately stop the engine, disconnect the spark plug
wire, and examine the lawn mower for damage.
•Maintain a sharp blade throughout the cutting season.
Periodically file down nicks on blade.
•Replace the blade when necessary with an original
Lawn-Boy replacement blade.
•Mow only dry grass or leaves. Wet grass and leaves
tend to clump on the yard and may cause the lawn
mower to plug or the engine to stall.
Wet grass or leaves can cause you to slip, contact
the blade, and seriously injure you.
Mow only in dry conditions.
Warning
•Clean clippings or leaves from the underside of the
lawn mower deck after each mowing. See Cleaning the
Lawn Mower Housing on page 14.
•Keep the engine in good running condition.
•Clean the air filter frequently. Mulching stirs up more
clippings and dust which clogs the air filter and
reduces engine performance.
•To achieve the best mulching action, set the lawn
mower height of cut so that the lawn mower cuts no
more than a third of the grass stem or a maximum of
one-inch (25 mm) long clippings. If you try to mulch
more or if the grass is very lush, the mulching action
will be poor. Under these conditions, use the side
discharge or grass catcher. A few days later, install the
mulch plate on your lawn mower to resume mulching.
Cutting Grass
•In the summer, cut the grass at the 2, 2-1/2, or 3-inch
(51, 64, or 76 mm) cutting height settings. Only cut off
about one-third of the grass blade. Do not cut below
the two-inch setting unless the grass is sparse or it is
late autumn when the grass growth begins to slow
down.
•When cutting grass over six inches tall, first mow
using the highest cutting height setting and walking
slower; then mow again at a lower setting for best
lawn appearance. If grass is too long and leaves
clumps on top of the lawn, the lawn mower may plug
and cause engine to stall.
•Alternate the mowing direction. This helps disperse
the clippings over the lawn for even fertilization.
If the finished cut lawn appearance is unsatisfactory, try
one or more of the following:
•Sharpen the blade.
•Walk at a slower pace while mowing.
•Raise the cutting height on your lawn mower.
•Cut the grass more frequently.
•Overlap the cutting swaths instead of cutting a full
swath with each pass.
•Set the cutting height on the front wheels one notch
lower than the rear wheels.
Cutting Leaves
•After cutting the lawn, make sure that half of the lawn
shows through the cut leaf cover. You may need to
make one or more passes over the leaves.
•For light leaf coverage, set all the wheels at the same
cutting height.
•If there are more than 5 inches (12.7 cm) of leaves on
the lawn, set the front wheels one or two notches
higher than the rear wheels. This makes it easier to
feed the leaves under the lawn mower deck.
•Slow down your mowing speed if the lawn mower
does not cut the leaves finely enough.
•If you cut up a lot of oak leaves, you can add lime to
your grass in the spring to reduce the acidity of the oak
leaves.

13
Maintenance
Note: Determine the left and right sides of the machine from the normal operating position.
Recommended Maintenance Schedule
Maintenance Service
Interval Maintenance Procedure
Each Use
•Check the stopping time of the blade brake. The blade must stop within three
seconds of releasing the bail; if it does not, contact an Authorized Service Dealer
for repair.
•Remove grass clippings and dirt from the under the housing.
25 Hours
•Check the blade and the engine mounting fasteners. Tighten them if they are
loose.
•Charge the battery for 24 hours monthly or as required. Charge for 24 hours
when storing the lawn mower and before the first mowing of the season (electric
start model only).
•Remove the grass clippings and debris from under the belt cover and near the
drive belt (self-propel models only).
•Grease the rear-height adjustor brackets (self-propel models only).
50 Hours
•Adjust the self-propel drive after changing the handle height, installing a new
self-propel drive cable, or if the traction drive belt slips.
•Remove and clean the air filter. Clean it more frequently in dusty operating
conditions.
•Clean, inspect, and gap the spark plug. Replace it if necessary.
•Sharpen or replace the blade; maintain it more frequently if the edge dulls
quickly in rough or in sandy conditions.
•Check for leaks in the fuel system and/or a deteriorating fuel hose. Replace
parts if necessary.
100 Hours
•Clean the exhaust port.
•Clean off grass clippings, debris, or dirt that can clog the engine air cooling fins
and starter. Clean the cooling system more frequently in dirty operating
conditions.
1Changethe engine oil after the first two operating hours.
Important Refer to your engine operator’s manual for additional maintenance procedures.
Caution
If you leave the wire on the spark plug, someone could accidently start the engine and seriously
injure you or other bystanders.
Disconnect the wire from the spark plug before you do any maintenance. Set the wire aside so
that it does not accidentally contact the spark plug.

14
Cleaning the Lawn Mower
Housing
A clean lawn mower housing provides the best cutting
performance. Check for grass buildup and clean it after
each use.
Washing Method
1. Move the lawn mower to a flat concrete or asphalt
surface near a garden hose.
2. Start the engine.
3. Hold the running garden hose at handle level and
direct the water to flow on the ground just in front of
the right rear tire (Fig. 19).
1093
1
Figure 19
1. Rear right wheel
The blade will draw in water and wash out clippings.
Let the water run until the clippings no longer come
out from under the housing.
4. Stop the engine and wait for all moving parts to stop.
5. Turn off the garden hose.
6. Start the lawn mower and let it run for a few minutes
to dry out the moisture on the lawn mower and its
components.
7. While the engine runs, engage and disengage the
traction drive several times to dry it out.
Scraping Method
If washing does not remove all debris from under the lawn
mower, tip it and scrape it clean.
1. Run the engine dry or remove the fuel when the engine
is cool.
Tipping the lawn mower may cause the fuel to
leak from the carburetor or the fuel tank.
Gasoline is extremely flammable, highly explosive
and under certain conditions can cause personal
injury or property damage.
Avoid fuel spills by running the engine dry or
removing gasoline with a hand pump; never
siphon.
Warning
2. Disconnect the wire from the spark plug (Fig. 14).
3. Tip the lawn mower onto its right side (Fig. 20).
1036
Figure 20
Note: When you tip the lawn mower onto its side, rotate
the blade as little as possible to avoid starting problems.
4. Scrape the built-up grass clippings and dirt from the
lawn mower housing with a hardwood scraper.
5. Tip the lawn mower upright.
6. Connect the wire to the spark plug.

15
Cleaning under the Belt Cover
Self-propel Models only
Under certain conditions, the clippings can collect under
the belt drive cover and in the pulley groove. This can
cause the belt to slip, the self-propel drive to lose power,
or the self-propel drive not to disengage.
Clean the grass clippings and debris from under the belt
cover every 25 hours of operation.
1. Remove the bolts from the belt cover (Fig. 21).
1
3
2
42
Figure 21
1. Belt cover
2. Bolt 3. Cable spring 4. Drive bracket
2. Unhook the cable spring from the drive bracket
(Fig. 21).
3. Remove the belt cover by pulling it straight out from
the engine.
Note: If the belt cover is pinched between the handle and
handle bracket, remove the handle before removing the
belt cover. For more information, refer to Adjusting the
Handle Height on page 6.
4. Remove the debris from under the cover and the pulley
groove.
5. Replace the belt cover by squeezing the sides together
and inserting the tabs on the belt cover into the
brackets on the engine base (Fig. 22).
m–4472
1
3
2
32
Figure 22
1. Belt cover
2. Tab 3. Bracket
6. Secure the belt cover with the screw.
7. Hook the cable spring onto the drive bracket.
Lubricating the Self-propel
Drive
Self-propel Models only
1. Wipe the grease fittings on the rear height-of-cut
adjustors (Fig. 23) with a clean rag.
1
Figure 23
1. Grease fitting (2)
2. Install a grease gun onto each fitting and gently apply
one or two pumps of #2 multi-purpose lithium grease
to each.
Important Excess grease may prevent the wheel
clutch from properly operating.

16
Adjusting the Self-propel Drive
Cable
Self-propel Models only
If the top speed begins to decrease on the lawn mower,
adjust the self-propel drive cable.
1. With the engine turned off, remove the bolts that
secure the belt cover (Fig. 24) and remove the cover.
2. Loosen the cable support nut (Fig. 25).
m–4205
12
3
4
Figure 25
1. Cable jacket
2. Cable support 3. Nut 4. Upper handle
3. Push the drive bracket down until it contacts the lawn
mower, then hold it in place (Fig. 26).
m–4209
1
2
Figure 26
1. Drive bracket 2. Push here
4. With the upper handle pushed back as far as possible
and while holding the drive bracket down, pull the
cable jacket down (toward the lawn mower) until there
is no slack in the cable (Fig. 25).
5. Tighten the nut on the cable support (Fig. 25).
6. Release the drive bracket.
7. Install the belt cover.
Servicing the Air Filter
Clean the air filter once every season or every 50
operating hours; clean it more frequently under dusty
conditions.
Note: Do not operate the engine without the air filter
element; extreme engine damage will occur.
1. Snap the air filter cover latch open and swing it to the
side (Fig. 27).
ÓÓÓÓ
ÓÓÓÓ
ÓÓÓÓ
m–3834
1
2
Figure 27
1. Filter 2. Cover
2. Remove the air filter.
3. Wash the air filter in laundry detergent or kerosene
(Fig. 28).
988
Figure 28
4. Squeeze the filter to remove excess liquid and blot it
dry with a paper towel or rag.
5. Saturate the air filter with SAE 30W oil (Fig. 29).
989
Figure 29
6. Squeeze the filter to distribute the oil evenly. Blot the
filter lightly with a paper towel to remove excess oil.
7. Replace the filter with the cleanest side facing the
carburetor.
Note: Ensure that the filter fully seats in the air box and
does not pucker, allowing air and dirt to pass directly
through to the carburetor.

17
Maintaining the Spark Plug
A spark plug that is dirty, pitted, carbon-covered, or has
worn electrodes may cause hard starting and poor
operation.
Clean or replace the spark plug once a season or every 50
operating hours, whichever occurs first. Use an NGK
BPMR4A spark plug.
1. Disconnect the wire from the spark plug (Fig. 14).
2. Remove the spark plug and clean it with a wire brush,
removing carbon buildup.
Important Do not sandblast the spark plug.
3. Check the condition of the plug for cracks and
damaged or worn electrodes. Replace it if necessary.
4. Set the spark plug gap at .035 inch (0.9 mm) (Fig. 30).
986
1
Figure 30
1. 0.035in. (0.9 mm)
5. Install the spark plug by hand, then torque it to
180 in-lb (15 ft-lb or 20 N⋅m).
6. Connect the wire to the spark plug.
Maintaining the Cutting Blade
A straight, sharp blade provides maximum cutting
performance. Regularly inspect and sharpen the blade.
The blade is sharp; contacting the blade can result
in serious personal injury.
Wear gloves or wrap the sharp edges of the blade
with a rag.
Warning
1. Disconnect the wire from the spark plug (Fig. 14).
2. Tip the lawn mower onto its right side (Fig. 20).
Inspecting the Blade
Carefully examine the blade for sharpness and wear,
especially where the flat and the curved parts meet
(Fig. 31A). Because sand and abrasive material can wear
away the metal that connects the flat and curved parts of
the blade, check the blade before using the lawn mower. If
you notice a slot or wear (Figs. 31B and 31C), replace the
blade; refer to Removing the Blade on page 18.
270
1
1
1
2
3
4
A
B
C
Figure 31
1. Sail
2. Flat part of blade 3. Wear 4. Slot formed
Note: Examine the mulching fan for any wear, cracks or
damage (Fig. 32). Replace it if necessary.
4
23
1
M–2909
Figure 32
1. Bladenut
2. Mulching fan 3. Blade 4. Blade driver
Note: For the best performance, install a new blade before
the cutting season begins. During the year, file down any
small nicks to maintain the cutting edge.
Danger
A worn or damaged blade can break, and a piece
of the blade could be thrown into the operator’s
or bystander’s area, resulting in serious personal
injury or death.
•Inspect the blade periodically for wear or
damage.
•Replace a worn or damaged blade.

18
Removing the Blade
1. Remove the blade nut and the mulching fan (Fig. 32).
2. Remove the blade from the blade driver (Fig. 32).
3. Examine the mulch fan for worn or bent blades.
Replace it if necessary.
4. Examine the blade driver for bent or sheared drive
lugs. Replace it if necessary.
Sharpening the Blade
File the top side of the blade to maintain its original
cutting angle (Fig. 33A) and inner cutting edge radius
(Fig. 33B).
153
1
m4783
2
AB
Figure 33
1. Sharpenat this angle only 2. Maintain the original
radius here
Note: The blade will remain balanced if you remove the
same amount of material from both cutting edges.
Note: Do not grind the blade more than 5 inch (127 mm)
from the outside ends and no less than 2 inch (51 mm)
from the trailing edge (Fig. 34).
990
2”
(51 mm)
5”
(127 mm)
Figure 34
Balancing the Blade
1. Check the balance of the blade by placing the center
hole of the blade over a nail or a screwdriver shank
clamped horizontally in a vise (Fig. 35).
1007
Figure 35
Note: You can also check the balance by using a
commercially manufactured blade balancer.
2. If either end of the blade rotates downward, file that
end (not the cutting edge or the end near the cutting
edge; refer to Figure 34). The blade is properly
balanced when neither end drops.
Installing the Blade
1. Ensure that the blade driver is installed on the
crankshaft. See Figure 32.
2. Install the blade over the lugs of the blade driver with
the curved ends toward the housing (Fig. 32).
3. Install the mulch fan into the blade recess (Fig. 32).
4. Secure the blade with the blade nut (Fig. 32)
5. Torque the blade nut to 47 ft-lb (63 Nm).
Note: Replace the blade nut after installing and removing
the blade four times. The blade nut’s locking power
diminishes and the blade nut could loosen if you do not
replace it.
6. Connect the wire to the spark plug.
Cleaning the Exhaust Port
Carbon deposit build-up in the exhaust port causes
excessive wear and power loss. Check and clean the
exhaust port every 100 operating hours.
1. Disconnect the wire from the spark plug (Fig. 4).
2. Drain the fuel from the fuel tank.
3. Tip the lawn mower onto its right side.

19
Tipping the lawn mower may cause the fuel to
leak from the carburetor or the fuel tank.
Gasoline is extremely flammable, highly explosive
and under certain conditions can cause personal
injury or property damage.
Avoid fuel spills by running the engine dry or
removing gasoline with a hand pump; never
siphon.
Warning
4. Remove the blade nut, the mulch fan and the blade.
See Removing the Blade on page 18.
5. Remove the blade driver by tapping it with a plastic or
fiber hammer in the direction of rotation (Fig. 36).
m–3835
1
Figure 36
1. Bladedriver
6. Remove the four capscrews that attach the cover plate
to the engine mounting plate (Fig. 37).
m–3836
1
3
2
4
5
Figure 37
1. Cover plate
2. Cap screw
3. Transfer pipe
4. Exhaust port
5. High temperature silicone
sealant
7. Remove the transfer pipe (Fig. 37).
8. Rotate the crankshaft slowly until the piston covers the
exhaust port (Fig. 37).
9. Using a wooden dowel, loosen the carbon deposits by
inserting a dowel into the exhaust port.
Note: Do not use metal tools; they can scratch the
piston.
10.Set the lawn mower upright.
11. Hold the blade control bail against the upper handle
and pull the starter rope several times to blow out any
loose carbon.
12.Run a bead of high-temperature automotive silicone
sealant along the edge of the engine mounting plate
where the cover plate will rest (Fig. 37).
13.Install the transfer pipe and cover plate (Fig. 37),
torquing the four cap screws to 75 in-lb (8.5 N·m).
14.Attach the blade driver, the blade, and the mulch fan
with the blade nut. See Installing the Blade on
page 18.
15.Torque the blade nut to 560 in-lb (47 ft-lb or 63 N·m).
16.Tip the lawn mower upright.
17.Connect the wire to the spark plug.
Changing the Fuse
Refer to Installing the Fuse on page 7.
Charging the Battery
Electric Start Model only
Battery posts, terminals, and related accessories
contain lead and lead compounds, chemicals
known to the State of California to cause cancer
and reproductive harm. Wash hands after
handling.
Warning
Charge a new or stored battery for 24 continuous hours to
ensure a full charge. Charge the battery for 24 hours every
month (every 25 starts) or as needed.
1. Stop the engine and wait for all moving parts to stop.
2. Disconnect the wire from the spark plug (Fig. 4).
3. Remove the key from the switch.
4. Connect the lead of the battery charger (supplied with
your lawn mower) to the wire harness lead.

20
m–5145
12
Figure 38
1. Wire harness lead 2. Battery charger lead
5. Plug the charger into a 120V AC power outlet.
6. Charge the battery for the specified time.
7. Unplug the battery charger.
Important Use only the Lawn-Boy charger; other
chargers could damage the battery. Always use the
charger indoors and charge the battery at room
temperature (70F or 22C) whenever possible.
8. Connect the wire to the spark plug.
Disposing of the Battery
Important Do not dispose of used batteries in your
regular trash.
Important Recycle or dispose of a sealed lead (acid)
battery according to local codes.
Incinerating, landfilling, or mixing of sealed lead (acid)
batteries with the municipal solid waste stream is
prohibited by law in most areas.
Return this battery to a federal- or state-approved sealed
lead (acid) battery recycler.
Contact your local waste management officials for more
information regarding the environmentally sound
collection, recycling, and disposal of the battery.
Emptying the Fuel Tank
1. Stop the engine and wait for it to cool down.
2. Disconnect the wire from the spark plug (Fig. 4).
3. Remove the cap from the fuel tank.
4. Use a hand pump to syphon the fuel into a clean
approved gasoline container.
5. Connect the wire to the spark plug.
6. Run the engine until it stops.
7. Start the engine again to make sure that all the
gasoline is out of the carburetor.
Storage
To prepare the lawn mower for off-season storage,
perform the recommended maintenance procedures.
Refer to Maintenance on page 13.
Store the lawn mower in a cool, dry place. Cover the lawn
mower to keep it clean and protected.
Preparing the Fuel System
Gasoline can vaporize if you store it over long
periods of time and explode if it comes into
contact with an open flame.
•Do not store gasoline over long periods of time.
•Do not store the lawn mower with gasoline in
the fuel tank or the carburetor in an enclosure
with an open flame. (For example, a furnace or
a water heater pilot light.)
•Allow the engine to cool before storing it in any
enclosure.
Warning
1. Empty the fuel tank using a hand-type siphon only.
2. Run the lawn mower until the engine stops from
running out of fuel.
3. Prime the engine and start it again.
4. Allow the engine to run until it stops. When you can
no longer start the engine, it is sufficiently dry.
Preparing the Engine
1. Remove the spark plug.
2. Using an oil can, add about one tablespoon of oil to
the engine through the spark plug hole (Fig. 39).
1009
Figure 39